package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
//        loadServlet();
        loadConfig();

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        while (true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            String url = request.getUrl();
            //处理地址  取出访问项目  具体servlet地址信息
            String contextName = url.split("/")[1];
            String servletName = url.split("/")[2];


            List<Host> hosts = mapper.getHosts();
            //循环查找请求所传得方法与类信息
            for (Host host : hosts) {
                List<Context> contexts = host.getContexts();
                for (Context context : contexts) {
                    if (context.getPath().equalsIgnoreCase(contextName)) {
                        List<Wrapper> wrappers = context.getWrappers();
                        for (Wrapper wrapper : wrappers) {
                            if (wrapper.getUrl().equalsIgnoreCase("/" + servletName)) {
                                wrapper.getServlet().service(request,response);
//                                httpServlet.service(request, response);
                            }
                        }
                    }
                }
            }

            // 静态资源处理
//            if(servletMap.get(request.getUrl()) == null) {
//                response.outputHtml(request.getUrl());
//            }else{
//                // 动态资源servlet请求
//                HttpServlet httpServlet = servletMap.get(request.getUrl());
//                httpServlet.service(request,response);
//            }

            socket.close();

        }


        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/


        //System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        /*while(true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }*/


    }


    private Map<String, HttpServlet> servletMap = new HashMap<String, HttpServlet>();

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private List<Wrapper> loadServlet(String path, String appBase) {


        try {
            ClassLoader classLoader = new MyClassLoader(appBase);

            InputStream resourceAsStream = new FileInputStream(new File(path));
            SAXReader saxReader = new SAXReader();

            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Wrapper> wrappers = new LinkedList<>();


            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();

                Class<?> clazz = ((MyClassLoader) classLoader).findClass(servletClass);

                Wrapper wrapper = new Wrapper();
                wrapper.setUrl(urlPattern);
                wrapper.setServlet((HttpServlet) clazz.newInstance());
                wrappers.add(wrapper);
//                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());

            }

            return wrappers;

        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    private Mapper mapper = new Mapper();

    /**
     * 加载解析配置文件.
     */
    private void loadConfig() {

        /**
         * 加载server.xml配置文件为输入流.
         */
        InputStream is = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();
        try {
            /**
             * 转换为文档对象.
             */
            Document document = saxReader.read(is);
            /**
             * 获取根节点.
             */
            Element root = document.getRootElement();
            List<Element> hostElements = root.selectNodes("//Host");
            for (Element hostElement : hostElements) {
                /**
                 * 封装主机信息
                 */
                Host host = new Host();
                String hostName = hostElement.attributeValue("name");
                String appBase = hostElement.attributeValue("appBase");

                host.setName(hostName);
                File appBaseFile = new File(appBase);
                File[] files = appBaseFile.listFiles();
                /**
                 * 遍历webapp下的项目信息
                 */
                for (File file : files) {
                    if (file.isDirectory()) {
                        /**
                         * 封装项目信息
                         */
                        Context context = new Context();
                        String contextName = file.getName();
                        context.setPath(contextName);
                        File web = new File(file, "web.xml");
                        /**
                         * 取web.xml下面的servlet信息
                         */
                        List<Wrapper> wrappers = loadServlet(web.getAbsolutePath(), appBase + File.separator + contextName);
                        context.setWrappers(wrappers);
                        host.getContexts().add(context);
                    }
                }
                mapper.getHosts().add(host);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }


    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
